1. Technical Field
The present invention relates to an improved technology for a method of manufacturing a band-shaped glass, which involves forming a band-shaped glass while being drawn downwardby, for example, an overflow downdraw method, followed by changing a conveying direction of the band-shaped glass to a lateral direction.
2. Background Art
In recent years, flat panel displays as typified by a liquid crystal display, a plasma display, an OLED display, and a field emission display have become widespread in place of CRT displays, which have conventionally been widespread, from the viewpoint of achieving space saving and the like.
There has been a demand that the OLED display, among other displays, be folded or rolled to facilitate its carriage, and be usable even in a shape conforming to a curved surface as well as a flat surface.
To meet this demand, a resin film may be applied as a substrate of the OLED display in consideration of high flexibility thereof. However, the light emitting element to be used in the OLED display is degraded when being exposed to gas such as oxygen and water vapor, and hence it is preferred from this viewpoint that a glass substrate having higher gas barrier property than the resin film be applied as the substrate of the OLED display.
However, the glass to be used in the substrate is vulnerable to tensile stress and thus low in flexibility unlike the resin film. Therefore, when the tensile stress is applied to the surface of the glass substrate due to bending of the glass substrate, the glass substrate may be damaged. Thus, there is a demand for higher flexibility of the glass substrate to be used in the OLED display.
Further, when solar cells and OLED lighting devices as well as displays can be mounted on the surface of an object including a curved surface, such as a body surface of an automobile and a roof, post, and exterior wall of a building, the range of uses of those devices is widened. Thus, there is a demand for higher flexibility of even a glass substrate and a cover glass to be used in those devices.
In addition, there is a demand from the market for further thinning of those devices such as displays, solar cells, and OLED lighting devices. Along with this, there is a demand for thinning of even a glass substrate and the like to be used in those devices.
To meet those demands for thinning and higher flexibility of the glass sheet, the use of a film-shaped glass having a thickness of 300 μm or less is proposed. Such a film-shaped glass is obtained by cutting a band-shaped glass into a predetermined length.
Such a band-shaped glass can be manufactured successively through use of, for example, an overflow downdraw method. In this case, as disclosed in, for example, Patent Literature 1, the band-shaped glass is formed while being drawn downward, and then the conveying direction of the band-shaped glass is changed to the lateral direction. With this operation, the subsequent processes for the band-shaped glass are facilitated.